<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title></title>
    <style>
        ul{
            list-style: none;
            padding: 0;
        }
        .zoom-box{
            width: 452px;
            position: relative;
        }
        .small-box{
            position: relative;
            border: 1px solid #ccc;
        }
        .small-box img{
            width: 100%;
            height: 100%;
        }
        .small-box .square{
            position: absolute;
            left: 0;
            top: 0;
            background: yellow;
            opacity: 0.5;
            /*display: none;*/
        }
        .small-box .mask{
            width: 100%;
            height: 100%;
            position: absolute;
            top: 0;
            left: 0;
        }
        .img-list ul::after{
            clear: both;
            content: '';
            display: table;
        }
        .img-list ul li{
            float: left;
            padding: 6px;
        }
        .img-list img{
            width: 50px;
            height: 50px;
            margin: 10px;
            border: 2px solid transparent;
        }
        .img-list img.active{
            border: 2px solid red;
        }
        .big-box{
            position: absolute;
            top: 0;
            left: 100%;
            margin-left: 2px;
            border: 1px solid #cccccc;
            width: 500px;
            height: 500px;
            overflow: hidden;
            display: none;
        }
        .big-box img{
            position: absolute;
            top: 0;
            left: 0;
        }

    </style>
</head>
<body>
    <!-- 布局-->
    <div class="zoom-box"><!-- 容器-->
        <div class="small-box"><!-- 小图片容器-->
            <img src="./../images/reba1.jpg" alt=""/>
            <div class="square"></div><!-- 鼠标选中框-->
            <div class="mask"></div><!-- 鼠标悬浮位置-->
        </div>
        <div class="img-list"><!-- 图片列表-->
            <ul>
                <li><img class="active" src="./../images/reba1.jpg" alt="" data-small="./../images/reba1.jpg"
                         data-big="./../images/reba1.jpg"/></li>
                <li><img src="./../images/reba2.jpg" alt="" data-small="./../images/reba2.jpg"
                         data-big="./../images/reba2.jpg"/></li>
                <li><img src="./../images/reba3.jpg" alt="" data-small="./../images/reba3.jpg"
                         data-big="./../images/reba3.jpg"/></li>
                <li><img src="./../images/reba4.jpg" alt="" data-small="./../images/reba4.jpg"
                         data-big="./../images/reba4.jpg"/></li>
                <li><img src="./../images/reba5.jpg" alt="" data-small="./../images/reba5.jpg"
                         data-big="./../images/reba5.jpg"/></li>
            </ul>
        </div>
        <div class="big-box"><!-- 放大镜-->
            <img src="./../images/reba1.jpg" alt=""/>
        </div>
    </div>

    <script>
        //获取要操作的元素
        var smallbox = $('.small-box .mask');
        var smallimg = $('.small-box img');
        var square = $('.square');
        var bigbox = $('.big-box');
        var bigimg = $('.big-box img');
        var imgs = $all('.img-list img');

        //鼠标经过图片列表显示被选中，实现图片切换
        for(var i = 0; i < imgs.length; i++){
            imgs[i].onmouseover = function(){
                for(var j = 0; j < imgs.length; j++){
                    imgs[j].className = '';
                }
                this.className = 'active';

                //改变对应的图片链接
                smallimg.src = this.getAttribute('data-small');
                bigimg.src = this.getAttribute('data-big');
            };
        }

        //鼠标移入放大器显示并设置选中框的大小
        smallbox.onmouseover = function(){
            square.style.display = 'block';
            bigbox.style.display = 'block';
            //位置w/smallimg.w = bigbox.w/bigimg.w
            square.style.width = bigbox.offsetWidth * smallimg.offsetWidth/bigimg.offsetWidth + 'px';
            square.style.height = bigbox.offsetHeight * smallimg.offsetHeight/bigimg.offsetHeight + 'px';
        };
        //鼠标移出放大器隐藏
        smallbox.onmouseout = function(){
            square.style.display = 'none';
            bigbox.style.display = 'none';
        };

        //放大器移动
        //获取鼠标的位置
        smallbox.onmousemove = function(ev){
            var oEvent = ev || event;
            var x = oEvent.offsetX - square.offsetWidth/2;
            var y = oEvent.offsetY - square.offsetHeight/2;

            if(x < 0){
                x = 0;
            }
            if(x > smallbox.offsetWidth - square.offsetWidth){
                x = smallbox.offsetWidth - square.offsetWidth;
            }
            if(y < 0){
                y = 0;
            }
            if(y > smallbox.offsetHeight - square.offsetHeight){
                y = smallbox.offsetHeight - square.offsetHeight;
            }

            //给选中框定位
            square.style.left = x + 'px';
            square.style.top = y + 'px';

            //给放大器定位  x/? = smallimg.w/bigimg.w
            bigimg.style.top = -y * bigimg.offsetWidth/smallimg.offsetWidth + 'px';
            bigimg.style.left = -x * bigimg.offsetHeight/smallimg.offsetHeight + 'px';

        };

        //通过名称查找某个元素
        function $(name){
            return document.querySelector(name);
        }
        //通过名称查找相同的一组数据
        function $all(name){
            return document.querySelectorAll(name);
        }
    </script>
</body>
</html>
